Wiring issue!

Im afraid im going to have to strip the engine loom out asap because the running issues today reached an nicely dangerous level wear by its started running lean on boost intermittently, the MF2 is working at the time and the FCD is working fine aswell (I even tried a different FCD). The only way it doesnt occur is to give it everything from a standing start so it hits full boost and only the MPI is working, so i no its an spi issue as usual.........may be carless for a while again until i get my new loom fitted

jason

Hope you get it sorted out what's it like to strip it out bet it's annoying when settin off bet people think you can't drive properly.

its not that bad,,,,,space is an issue but with the boost pipes etc out off the way and the front bumper off its not that bad at all, ill have to splice into the loom though to wire up the MF2 again.
Its the only thing left that could be causing these issues seen as a really have changed everything other than the loom, never mind i need to just get it sorted and then a may well have a drivable car again lol.

may aswell fit the new front mount cooler while in at it.

jason

how do you know the SPI isnt working then? Theres no chance it could just be a worn or underrated fuel pump? since you say its fine from a standing start..

munkul wrote:"how do you know the SPI isnt working then? Theres no chance it could just be a worn or underrated fuel pump? since you say its fine from a standing start.."

Its along story mate but here goes you never no something may twig and you may have a view point on it that i haven't seen -

firstly the fuel pump is a new RS2000 255lph fuel pump and the issue was there before the pump was fitted, Basically right from the days when the car ran SPI only ive had a hesitation around 2000rpm which evolved into many intermittent faults like bad starting (mega rich on start up), bad idling on and off, bad hesitation from momentary weak fueling before the MF2 kicks in every so often.
Some days the car can be totally fine/smooth and fuling is fine and others the symptoms can make the car undrivable altogether which as you can imagine makes a fault harder to find and understand seen as the issues vary massively day to day.
If i sit on the spot and slam the throttle down from idle the engine coughs and splutters for around/upto 6-7 seconds before it slowly and roughly starts to climb through the revs (weak mixture) then turbo will come in kicking the mpi in then all is ok as its blasts upto the rev limit (sometimes full throttle from idle can simple make the engine cut out), from cold there is no problem at all it will rev from idle amazingly well which always suggested lambda or coolant temp issue to me?? but believe me when i say ive changed every single engine sensor many times so they all work fine. All the earths are good throughout the engine bay and the ECU is working fine (swapped it many times with other units).
The problem has been there right from when i got the car just no where near as bad and nobles have always been able to set the car up without an issue as the on boost fueling has always been cock on............its just nown again it decides to do this where the map pressure goes over 0 and its just hesitates and dies from being lean.....and like i say at this time the MF2 is still working but without the assistance off the single point injector....the spi unit doesn't stop playing a part in the on boost fueling until max boost where the mpi is virtualy stand alone so if the SPI stops working anything below 15psi it will cause a lean mixture which as you now is dangerous.

ive had a few auto electricians stick there head under the bonnet with me and theyve all said due to the fact that all the sensors are working fine etc etc that it seems to be a loom breaking down (the wiring is pretty poor....all the wiring is hard and brittle).

So there it goes, there is my issue. lived with it for to long trying the odd thing day to day but i feel its time to strip the loom out and try another.......whats your thought??

jason

Munkul - sorry mate i edited your post as a reply,,,its unchanged anyway
the quote and edit buttons are so close

jason

hmm sounds like you are right then. Whats the plan then - measure resistance through each wire? or just replace the whole lot?

munkul wrote:hmm sounds like you are right then. Whats the plan then - measure resistance through each wire? or just replace the whole lot?

im going to go for it and change the hole loom

around the time me and the electrician where testing my loom he was doing a mk 1 mondeo with a starting issue...the loom tested ok but a new one cured the issue so we both decided that a problem this intermittent may go totally unnoticed so best to change it.......just my luck!

Id rather it shut down one day and not start again, that way i could find the issue properly, that would be to easy though ey haha

thanks

jason

you better get it sorted before 31st im not towing you around lol

only joking hope it cures the problem mate

me too......failing that its some kind off ghost in the car, which again is just about my luck haha.
Im going to crack on with it asap i just need some kind off transport to work then i can get stripping......the wiring off course

jason

i hate intermitent faults lol but to me it does sound like the loom is failing

good luck

little update, i managed to nurse the car home from work today and i was feeling intrigued about this new on boost fueling issue its developed.
Knowing the majority off the fueling is done by the MF2 and MPI once the boost kicks in i wanted to take the car on a run and observe the MF2 in action..........the MF2 is great for self diagnosis because there is an red LED that lights up to tell you the MF2 is seeing 0psi (atmospheric pressure) and another green LED that is triggered by the MF2 when it starts to inject fuel....aswell as LED's that indicate the revs input in 1000rpm intervals.
I placed the MF2 on the dash so i could see it clearly and started the test, i quickly noticed that occasionally the green injector light would go off while on boost causing the weak mixture! as if the the map signal was being disrupted, i stripped the mf2 looking for loose solder or corrosion etc but its a very basic and well built bit off kit and its as new, so i checked the boost/vac line for restriction that seemed fine so i just stripped the line out and replaced it anyway along with shortening the pipe and looking for leaks. I also tested the MF2 was working ok by reving the engine upto 2k and forcing air into the map sensor which instantly sent the lambda gauge into rich and there was no sign off the mf2 cutting fueling off.
I took the car out after and its all fueling fine but i now its done this before and between the engine loom and the MF2 ive got a very unreliable setup....... after market management asap i think!!
Ive booked two days off work when i come back from holiday so i can strip out the old loom and fit the new one so that will hopefully cure the biggest running faults....

jason

get it running right co u takin me out in it soon boyo